21044870 has 64 divisors (see below), whose sum is σ = 47803392. Its totient is φ = 6480000.

The previous prime is 21044833. The next prime is 21044873. The reversal of 21044870 is 7844012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21044873) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 116180 + ... + 116360.

It is an arithmetic number, because the mean of its divisors is an integer number (746928).

Almost surely, 2^21044870 is an apocalyptic number.

21044870 is an abundant number, since it is smaller than the sum of its proper divisors (26758522).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21044870 is a wasteful number, since it uses less digits than its factorization.

21044870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 357.

The product of its (nonzero) digits is 1792, while the sum is 26.

The square root of 21044870 is about 4587.4688009838. The cubic root of 21044870 is about 276.0887745655.

Adding to 21044870 its reverse (7844012), we get a palindrome (28888882).

The spelling of 21044870 in words is "twenty-one million, forty-four thousand, eight hundred seventy".